Weed control, maize (Zea mays L.) metabolism, and rhizosphere microbiome of hollow mesoporous silica nanoparticles loaded with S-metolachlor and ZnO quantum dots.

BACKGROUND: Conventional pesticide formulations employ large amounts of organic solvents, raising concerns regarding their environmental contamination, pesticide residues, and potential toxicity to non-target organisms. Hollow mesoporous silica nanoparticles (HMSNs) are non-toxic to both animals and plants, making them a suitable candidate for pesticide loading and delivery studies.

RESULTS: HMSNs with an average particle size of 165 nm were synthesized using a self-template method. Fluorescein isothiocyanate was successfully conjugated to the HMSNs to enable the investigation of their transport and distribution in maize. The S-metolachlor (S-met) loading efficiencies of HMSN and HMSN@ZnO quantum dots (QDs) carriers were 18.7% and 10.7%, respectively. Application of nanocarriers did not adversely affect weed control efficacy, maize growth, or plant antioxidant enzymatic activity. No detrimental effect of the nanocarriers was observed on crop and weed control, and no clear differences were observed in metabolites and soil microbial dynamics. HMSN@S-met@ZnO QDs treatment increased the proportions of lysobacter and blastococcus compared to the control, whereas the EC treatment exhibited a relatively different distribution pattern for sphingobacterium and pseudomonas. Actinophytocola algeriensis and sphingomicrobium were selectively enriched in nanocarriers-based treatments relative to the control and conventional S-met EC treatment. The active microbial community was predominantly composed of species affiliated with entotheonella and pseudomonas based on the metatranscriptomic species profiling.

CONCLUSION: The nanocarrier formulations were safe for maize and maintained effective weed control, and significantly modulated metabolites of maize plants and the microbial community composition in the soil. © 2026 Society of Chemical Industry.